Apparatus for treating liquids with gases



i2; aC 2,313,654

APPARATUS FOR TREATING LIQUIDS WITH GASES Filed Nov. 19, 1940 2Sheets-Sheet l INVENTOR M m Y 5 March 9, 1943. G. MacLEAN 2,313,654

APPARATUS FOR TREATING LIQUIDS WITH GASES Filed Nov. 19, 1940 2Sheets-Sheet 2 r INVENTOR fiordaiz Ml'L'fliZ M M1- ATTORNEYS PatentedMar. 9, 1943 atfis tmwm us g qnids with;

flfl uid LP iii sus'jiensidh is 'essritielly hendled in the same menn HAnd, for eoiivenier'icgi heijein' ter ie'ls 'as liquids? Without .ie a uI m eses" i m d mlr actwimhe w n; or Withsolids suspended iii thel'idiiid. Y

The present invention is an improveme auxiliaryapathsi the p 1y the hoodrmgEnd upvqardiy intothe e ten eiiztheiimpellergand the fiilxiliarybathS b'eing upwardly above the hood ring and dowhwiird lyv-intothe-center 2oz ttheimpellen K-gss conduit leads downwardlyetoi-arzpomtad j ae'ent to' the eeii tennfzthaimpeller; andth'eT'iiquidmoven'ient pim duc'es ta; low-:pressureiaree near theicnterof t impellen with the'mesultithat. ga's -is uckd' ddwwagdly1th1oug'iiiethe' vconduit;- and' i z- 'mixed with the iiquidPas,it isgactediuponfiby the'impellenar f --This prior: apparatus:hasb'eenhighlyls icess iceswherenthegliqmd-e leveliinsthe -treatmenttail-ill could he maintained; constant? limughoufisthei: Homes/eggwith;someepnoeessesizthefiliqy' D QQQ YSQV uid level changes, a byexpansion or contna; m f iquid: eza @h mer ite mr R be nvolvedvidingihiimpelletl biases;

-n-any such was the iqilid 'le'vel changesdfining the :t'reatment andthe aboardtus:tof'fPhtent51,916j956 is sens iti ve flo liquid levelchange, 'in the': s'ense that the' chang in liquid level-causes the gas:suction eapacity to 'vewob je'ctiofiablyi Whenth'e' fias 'sucti'bnc'apacity be comes impaired; the 'overall efliciencw of the ap-'-paratus is redi1ced', the mo't'or liadihgds varied; snd'the time-oft'reatment is 'piolongedr= ii wAs'Haspecific example: of impairment'dfgas section; BIL-6811 cite 8; 2'Z inch' senator according tab-Patent1,916,956 whichaopx aiteweflieiently with the liquid level: l/iiinchesibovth hood il'n but which would'ihaveiits gassuction r eddcedby ne i; halfnif the liquid .level idropped' td Vi inch -aboveminorchangesin: 13118211385 suctiononna be, occasioned QbYs :variation of thei within;relativelywidevlimitsiwv motion :loadin? and zoverelllwaetiommast: ;be;:mlsiirn-fi tainddzat approximatelyioptimifln"iaziueseziespite relatively widewariation si in fiaher liquid level Astill further object of the iri iientionfiiito m to? uniformity ofperformence under varyin' 'co' ditions.

with 'librizontalrail ingafins. constmctionfw-asiarrivediat exfierimentally .aiter theifai'luneof many other" change F or mod-iflcaitionsi,accomplish the-de'siredi re sult; \Thee'mcacy;of=.the:-.horizonta1z-flns he's beens iamplyatdemonstrated With thefinsiddedg'itheii' 27.. inchraeraton piceviouslfi xieferreditdmaintained its gas; suctiomcapaeitw substantially mnimpairedi iw-hlleuth z lquid; level; VZHQQ'ifTOHDS iniches 3prhoiv the hood :ring,0 1 5: inches. aboveaitr, J ustih'ow thei ;fiz, "D Qd e thisdesiredmesultzisi hotaltogethens certain et present. It is believed thatthe maine tenanee-of strong. gas suctionadespite wide :vari-.. ations inliquid level is related in some waywta a redistribution of liquid flow,betweemthetop and bottom oL-the imp l er Pl sthe;.esta.b11shment withinthe impeller of more definite or localized outwardly moving streams ofliquid which more eifectively move the gas outwardly as it is drawn intothe center of the impeller. However, this does not seem to be a completeexplanation as similar results did not follow from other structuralchanges which would similarly affect the liquid fiow in the impeller.

Fig. 1 is a partly diagrammatical vertical section showing illustrativeapparatus embodying the present invention, the section being takenapproximately on the line l-I of Fig. 2.

Fig. 2 is a horizontal section taken in general on the line 2-2 of Fig.l, a portion of the hood being broken away to expose the constructionbeneath it.

Fig. 3 is a vertical section showing the impeller only, the sectionbeing taken approximately on the line 3-3 of Fig. 1.

A tank I, adapted to contain the liquid to be processed, is providedwith a suitable valved inlet and outlet pipe 2 and with an overflow pipe3. A plurality of rods 6 (four shown) depend from a superstructure (notshown) and suspend a stationary flow controlling structure designated asa whole by 1. A depending vertical shaft 9 carries and supports a rotaryimpeller designated as a whole by ID. Surrounding the shaft 9 is a gasconduit I9 through which gas is adapted to be inducted. The support andmotor drive for shaft and the support for gas conduit I9 and rods 6 maybe of any suitable type as, for example, that disclosed in my priorPatent 1,976,956.

Thestationary structure 1 comprises a hood member or ring i2 shaped muchlike the outer portion of an ordinary tin wash basin turned upside down.The hood member l2 may be cast of metal and integral with it there maybe formed curved deflecting blades i3 which extend vertically downwardlyfrom the hood M. The hood may be provided with apertured bosses i4 (fourshown) adapted to receive and be clamped to the rods 8 to support thestationary structure 1 and to provide for its accurate vertical locationwith respect to the impeller. The hood may also be cast with bosses 4,4, which are used only in cases where it is desired to sever the hoodring along line 8, 8 so that the halves can be inserted into a tankthrough a relatively small manhole. In these cases, the bosses I, 4 aredrilled and tapped to receive bolts for clamping the two halves of thehood ring together. The hood i2 is provided with a central hole I6 whichsurorunds the bottom of conduit l9, thereby providing an annular liquidinlet port H.

In operation the tank is filled with liquid to be'treated (e. g.vegetable oil) to a depth which will completely submerge the structure1, giving a liquid level such as that illustrated by line 15.

When the impeller is rotated, it draws liquid up-- wardly from thebottom and also draws liquid downwardly from the top through annularport ii. The flow of liquid through the impeller creates a low pressurezone adjacent the hub of the impeller. Thus, gas is drawn throughconduit I! and is entrained with the liquid so that the impeller blades29 cause streams of mixed gas and liquid to flow outwardly in asubstantially horizontal direction to strike deflector blades i3 and beprojected downwardly by hood ii. The main paths of circulation are asindicated by arrows A, C, and the auxiliary paths as indicated by arrowsA, B.

The impeller shown is of the forward discharge type and in accordancewith the present invention the blades 29 are provided with trailinghorizontal fins 30. These fins are preferably on the ,lower edges of theblades, and I prefer to have 30 act, as previously pointed out, to givethe apparatus more uniform performance, particularly with respect to thegas suction effect occurring throughout a variation of liquid level inthe tank.

Also more uniform motor loading, and better overall performance therebyresults.

The term impeller as used herein means a rotating device which draws inliquid along lines of fiow substantially parallel to the axis ofrotation and discharges the major portion of the liquid in planessubstantially perpendicular to the axis of rotation.

Various arrangements and proportions of the fins 30 will produce thedesired result in varying degrees but the drawings show the bestproportions and arrangement which is now known to me.

I claim:

1. In apparatus for treating liquid with gases of the type in whichstreams of liquid and gas enter a rotary impeller and are discharged bythe impeller for circulation in a tank, the major portion of thedischarge being in planes substantially perpendicular to the axis ofrotation; the improvement which comprises: blades of the impeller beingprovided with trailing fins which occupy approximately 30% of the areabetween the blades.

2. In apparatus for treating liquid with gases of the type in which arotary impeller receives liquid from below and receives gas from above,the liquid and gas being mixed in the impeller and discharged therefromfor circulation in a tank, the major portion of the discharge being inplanes substantially perpendicular to the axis of rotation; theimprovement which comprises: lower portions of the blades of theimpeller being provided with elongated trailing fins extendinglengthwise of the blades from adjacent to the center of the impeller toauiacent to the tips of the blades.

3. In apparatus for treating liquid with gases of the type in which ahorizontal rotary impeller receives liquid from below and receives gasfrom above, the liquid and gas being mixed in the impeller anddischarged therefrom for circulation in a tank, the major portion of thedischarge being in planes substantially perpendicular to the axis ofrotation; the improvement which comprises: lower portions of the bladesof the impeller being provided with trailing fins which diminish theeffective area of liquid intake from the bottom of the impeller byapproximately 30%.

4. In apparatus for treating liquid with gases of the type in which ahorizontal rotary impeller receives liquid from below and receives gasfrom above, the liquid and gas being mixed in the impeller anddischarged therefrom for circuthe center of the impeller to adjacent tothe tips of the blades and are relatively wide adjacent to the tips ofthe impeller.

5. Inapparatus for treating liquid with gases of the type in which atank is provided with a submerged rotary impeller surrounded by a .sub-'merged hooded deflector ring, the impeller acting to draw liquid frombelow and draw both-liquid and gas from above, the liquid and gas being'mixed in the'impeller and being discharged.

therefrom into the hooded deflector ring for ensuing circulation in thetank: the improvement which comprises: the impeller being of the for.-ward discharge type and having its blades provided with trailing thiswhich reduce the eil'ective intake area from below by approximately 30%.

6. In apparatus for treating liquid with gases of the type in which atank isprovided with a submerged rotary impeilersurrounded byafsubmerged hooded deflector ring, the impeller acting to drawliquidirorn below and draw both.

liquid and gas from above, the liquid and gas being mixed in theimpeller andbeing discharged thereirom into thehooded deflector ring !orencirculation in the-tank; the improvement which comprises: the impellerbeing ,of the forward discharge type and having the lower edges of itsblades provided with trailing flns.

'7. In apparatus for treating liquid with gases of the type in which atank is provided with a submerged rotary impeller surrounded by asubmerged hooded deflector ring, the impeller acting to draw liquid frombelow and draw both liquid and gas from above, the liquid and gas beingmixed in the impeller and being discharged therefrom into the hoodeddeflector ring for ensuing circulation in the tank; the improvementwhich comprises: the impeller having the lower edges oi the bladesprovided with trailing flns.

' 8. In apparatusior treating liquid with gases of the type in which atank is provided with a submerged rotary impeller surrounded by a submerged hooded deflector ring, the impeller act-v ing to-draw liquid frombelow and draw both liquid and gas from. above, the liquid and gas beingmixed in the impeller and being discharged therefrom into the hoodeddeflector ring for ensuing circulation in the tank; the improvementwhich comprises: the impeller being of the terward discharge type andhaving the lower edges of the blades provided with trailing flnsextend-' ing throughout the length of the blades, the

' fins being oi substantial width adjacent to the tips of the blades andreducing the eiiective inapproadmate130%.

take area from below by GORDON MACLEAN.

